Is the relinquished portion of the inheritance to be divided according to Islamic law or equally between the deceased's wife and children?

The estate of a deceased man who left behind a mother, a wife, and children is divided as follows: The mother receives one-sixth due to the presence of inheriting offspring. The wife receives one-eighth due to the presence of inheriting offspring. The remaining estate goes to the children, with the male receiving the share of two females. If the mother dies before the estate is divided, her share from her son is set aside and inherited by her own heirs, because inheritance automatically becomes the property of the heir by force of law. If the heirs relinquish their share of their mother's estate, this relinquishment is considered a gift, and they may divide it however they wish.